Baldur's Gate 3 gives you a lot of options when it comes to choosing who to side with, choosing who to work with, and deciding who you agree with. It's a game with paths upon paths upon paths, and even seemingly small side quests have choices that you have to make.
Should you side with Madeline or He Who Was?
You'll come across a character called He Who Was during your travels in the Shadowlands, and he'll ask you to help him judge a character called Madeline, who he says has committed a heinous crime.
You have to go to an abandoned bar in Reithwin Town called the Waning Moon Tavern, which is filled with corrupt patrons. In that room, you can find a book that has details on what Madeline allegedly did. It turns out, Madeline seemingly got two men killed completely accidentally after they got extremely drunk in her bar.
Speaking to Madeline once you return to He Who Was, you'll find out that she claims to not have known that the Dark Justicar she was reporting to would kill the two patrons. Here, you're given a decision. You can either spare Madeline judgment, which will cause He Who Was to attack her, or you can side with He Who Was. However, siding with He Who Was can also result in He Who Was stabbing himself if you tell Madeline to stab herself, which gives you easy access to his loot.